I'm rather surprised that it hasn't been done yet. There was an Italian (I think) movie in the 60s, but it's very hard to find. I've never seen it. (And from what I've heard they directly did the Platonic dialogs; mine will be a combination of several historical sources, as well as my own fictional narrative details.)
The Pre-Socratics are very interesting, but there's often only a very little amount of surviving sources to tease out their thought and worldview. One of the most fascinating things from that era for is Thucydides' Peloponnesian War. Anyway, have fun as you dig into the Greeks!