The following are the cards which would suggest sexual abuse for me personally. As usual I am not claiming that this list is in any way perfect, and of course most of the cards will be modified by others around them to indicate subtleties, and of course court cards in particular will indicate people involved.
II High Priestess: There's no getting away from it that the secrecy element of this card could be twisted into the secrecy involved in hiding abuse.
IX Hermit: This is another of those cards which has a distasteful undertone. Far from simply being the Golden Dawn's 'Magus of the Voice of Light, the Prophet of the Gods', a friend of mine refers to this as the 'wanker' card! The hermit is a card of isolation and thus can rebound on the target of abuse as meaning isolation with the abuser. There is literally nobody to turn to here at all, such a common experience in an abusive situation.
XV The Devil: This one rather speals for itself but I feel that more obviously it could refer to a Joseph Fritzel type of abuse, of literally being tied up in a cellar, for example. There are overtones of addiction in this card, which in sexual terms I suppose translates into an inability to keep away from sex, and specifically an inability to get away from a dangerous sexual expression. I would not see it as referring to 'Satanic ritual abuse', which I see as a common folk belief with no real existence in our culture. In a reading if the querent started talking about Satanic ritual abuse I would stop the reading and refer them to the police at once. No prosecution will ensue, because nobody has ever come up with the evidence that this actually happens.
XVIII The Moon: The friend who refers to the Hermit as the wanker card calls this one the anus card! In an attempt to reclaim my reputation as being a reputable tarotist and this blog's reputation as a serious witchcraft blog, I would have to say that Waite refers to this trump as meaning that the mystery illuminated is our animal nature. There is an absence of 'higher' help here, and since it one of the weirder tarot cards, a sense that anything could happen, quite apart from the obvious sexual imagery of the moon and the towers.
3 of Cups: I have seen this considered as a card that refers to kinky sex, in the sense of a threesome, even though I don't get that impression from it myself. It could refer to a paedophile ring, I suppose, but I would think that that kind of thing would be better shown by the 10 of Pentacles.
6 of Cups: I am told that I have a personal bias towards reading this card in a 'reversed' way, which probably says more about me than you could wish to know! Actually I don't read with reversals unless I'm using an Eteilla deck, and prefer to see the upright and reversed meanings as shades of meaning within the card, but I definitely see this one as referring to childhood and specifically something horribly wrong with childhood. Tell me that it doesn't have to be that way and I will agree, but I will also caution against pretending that childhood is a happy time: for an awful lot of people it is awful.
7 of Cups: This one refers in a straightforward way to the threats and lies of the abuser. It should be approached with caution in a reading, because the survivor of the abuse will often have conflicted emotions towards the abuser, to the extent that people often report actually enjoying being sexually abused.
5 of Pentacles: The obvious reference is to the loneliness and isolation caused by abuse, the need to keep this secret which is actually damaging. The Morgan-Greer deck shows the female comforting the male who is injured and thus it may refer to a helper. It could of course mean an actual journey to get away from an abuse or a journey in the sense of lifting a stone on abuse and all the ensuing changes.
10 of Pentacles: Home, sweet home, and thus one of the most likely settings for sexual abuse possible. People are most likely to be abused, murdered, and so on, by somebody they know. The old-fashioned concept of stranger danger is largely illusory. This card could also refer to family in a wider setting in that I'm sure a lot of paedophiles will introduce the child to any number of 'aunties ' and 'uncles'.
9 of Swords: Again a very literal image of sitting up in bed dreading what is going to happen.
Of course in a reading it is not enough to see that something has happened. So I have asked my tarot deck what to say to the person who has a history of sexual abuse. The card that leapt out at me as I shuffled was XXI The World! I was using my Morgan-Greer deck, and I think there was a message for me personally, that when the tarot reveals something to the reader, it also gives us a task. It is the task of the reader to help the querent end their history or cycle of abuse, by whatever means necessary. This of course may mean ringing the police, it may mean engaging in psychotherapy, it may mean a ritual to end the process. I find it interesting that the advice from tarot here is actually fairly non-specific, which is what I was expecting, and so must be tailored to the individulal circumstances. Some people are just not ready even to unpack their history of abuse. Some people may have had abuse and genuinely not remember anything about that time of their life (if that is the case, for Goddess's sake don't start telling them what you see, because 'recovered' memories can be the most dangerous things out there).
In the case of what to say to the colleague who asked me to read his cards, I get the answer 4 of wands. Hmm... That's a don't tell him, then. Or rather, it's a message to talk to him about family so that I wander up to the subject but don't actually go there and see what happens.