Colloquial Equivalent of: Speedy Gonzales
Speedy Gonzales as a cartoon character is translated to 飞毛腿冈萨雷斯. Not many Chinese know this cartoon character, but 飞毛腿 as a noun can be used to describe people running very fast. It literally means flying hairy legs.

Less frequently seen but still recognizable, you can use 神行太保. It's a nickname for a 水浒 character who is known to be able to run very fast. It literally means miraculously walking prime minister. In fact his job is the messenger.