Aside from leaving his gear sitting in the middle of the ring, Taker went to ringside and gave his wife, Michelle McCool, a kiss. Now would that matter so much of it was anyone else on the roster? Probably not but Taker is someone that almost never breaks kayfabe and he's never broken it in such a blatant way. It's normal to kiss your wife, of course, but Taker's "the Deadman", the "Lord of Darkness" and all that, which means he's got nothing to do with such mortal trappings. Outside of his biker gimmick, Taker's character has never been "human" in the same way as everyone else.
Now, this isn't a guarantee that he's retired, but it's a strong indicator given his old school mentality and protecting kayfabe, or at least protecting it as much as one can in this social media driven society.