I don't know how to see my creatures running speed (on running) but have you looked at the ground and see there are numbers? Well my creature has gone up to 85 in 7 seconds. I don't know if that is fast.
Viewing post in Fastest creature you've ever made?
That, that right there, is extremely fast. You can see speed by looking at the numbers on the side of the screen that pop up when you click on the previous generation best creature in the top right hand corner. Also, doing this means you’re looking at the previous generation, but there’s no way to view what speed the current is at.