^Not exactly. BOTH RUN AT 720P. But the Xbox 360 has a built in upscaler that upscales a 720p resolution to 1080p. So in reality, you're just getting an upscaled image of a 720p image. So technically that wouldn't make a single difference.
However, it has been proven that the xbox 360 (I have both 360 and ps3 running in HDMI) has slightly (sometimes not visible) better graphics. Note that it's really, really slight that you wouldn't notice it.
Now this comes from the FACT, that it's easier to code the XBOX 360 games than ps3 games. ps3 is harder to work with so that's why the ps3 versions wont have better graphics. They can only be on par with the 360 or slightly worse. Note that I am talking from facts not fanboyism.
As for pes, I cannot talk because I don't have both versions. But the demo looked really good in my ps3. Overall on par or slightly better than pes 10 graphics wise.