Coloring Pages for Kids
Alligator and Crocodile Coloring Pages

The easiest to identify difference between an alligator and a crocodile is that when it's mouth is closed, a crocodile's bottom teeth show while an alligator's doesn't (though you'll often see some of the alligator's front, top teeth). Also, an alligator's bottom jaw is larger than its top jaw.

Having said that, the coloring pages are "cartoon-ish" and most of them could be used to represent either animal.