It's confirmed as Mat, but don't make too much out of his depiction.

The red spear-of-the-dragon style head-band Sweet had given Perrin previously and Mat here is apparently one of the mistakes Harriet has asked Sweet to correct on the cover (if they go with that cover - they're apparently not sure yet they're gonna go with this painting/scene at all). This should have been Mat's classic hat. Another acknowledged mistake is apparently depicting Jain on the right as much younger than he is. The triangle on the door is also drawn upside down from Olver's instructions. The Tower shouldn't be in the woods either, Mat and Perrin both saw it in the middle of a field.

So according to Sweet, Noal is obviously a Forsaken who's now shed his mask of mirrors, and he's misled Mat (who has taken to wear a spear-of-the-dragon head-band in mockery of Elayne's and Aviendha's adoption), and Thom to the wrong Tower, and now he's drawing the symbol the wrong way to convince the other two they can't enter and to give up.