I'm not sure if you are asking about the iPhone side of the synching, but in MacOS 10.7.x you can reveal the iPod Photo Cache like this:
Your iPod Photo Cache is stored in a folder inside your Aperture Library Package. To view the iPod Photo Cache in the Finder select your Aperture Library, ctrl-click it, press "Show Package Contents" from the opo-up menu. This will open a Finder Window with the folders inside the package, and one of these is the iPod Photo Cache and you can browse it from the Finder. If you need access to this folder from a file chooser dialogue, drag this folder to the Finder sidebar for easy access.