I have never seen terminators do well against tau. They have a tendency to get munched much faster than you think they will (cough plasma rifle crisis suits cough)
That being said, what models do you have? If you can't change the list because of model restrictions .. not much use in getting advice on how to change the list .. yeah?
If you literally can't change the list at all, consider making the assault squad vanguard veterans. They can charge on the turn that they land, which can be enormous against tau. If you try and deep strike termies ... there will just be some bloody paste left the next turn.
Also, your librarian has literally useless powers for dealing with tau. GOI will get you into range more quickly. That might be useful for bringing your tactical squad close enough to shoot at him, and if you're intent on deep striking your termies it will get the teleport homer that much closer. You also might want to consider the ability that gives them all 5+ invulnerable saves, depending on how many crisis suits your opponent runs. I think GOI and the str 6 power are your best bets though.