He's short for 160, but he's not small. He's built like a tank. There's a reason he doesn't allow his fight night weight to be published. Canelo probably walks around at 190+ and drains down to 160.
Hes short for his build is the truth of it. When he was a teenager he was skinny and down at lower weights where his height was fine but if you think about it hes not much different height from floyd but way thicker set. The height difference really ramps up after 168 on, id say 6'1" is standard for a world level 168lb guy.