The English phrase is a well-known saying, and for your purposes I think you need a well-known Latin saying that carried approximately the same sense, rather than any direct translation. This would in case, as you say, be quite a challenge with this particular saying.

"Suum cuique” is one possibility. It springs to mind for me because I have recently been playing in a castle here in Dresden which has a very fine staircase with this motto built into it. You can see it in the reference, if you scroll down to the picture of the staircase. The direct back-translation would probably be “To each his own”, but I think it is at least one candidate for an equivalent to “Whatever turns you on”. It´s no exact equivalent, but might well be used in the same circumstances in which the English phrase is appropriate