The tomato plants may be reacting to the much higher level of sun they receive outside in the ground as opposed to in your house under lights or in a sunny window. They are undergoing what I have heard called "photo-bleaching". I have seen this happen to many tomato plants at the community garden where I have my plot, and many times they do recover. After about two weeks post transplant they should start putting out new dark green leaves that are adapted to dealing with the higher levels of sunlight. They will look pretty terrible until that happens, but barring any unforeseen weather events they should make it through. In the future, you should try to "harden off" your seedlings by exposing them to direct sun a little bit each day for a few days leading up to transplant. You can also try putting some row cover over them (that reduces light transmission by up 15-25% depending on thickness). Fabric row cover is available from most online garden suppliers like Johnny's or Gardens Alive.