The translucent epoxy grout from mapei is good, not clear enough to be an issue with adhesive shining through, (unless that's messy and poking up all over the place), it just kind of takes on the colour of the tiles and turns a shade or two darker than that, think greyish translucent Silicon. 🙂
I doubt if anyone will stock this at the moment, but all Mapei grouts can be special ordered within 7 days - and possibly from Tile Giant. PM one of there shops/members on this forum for info.