Here's a screenshot of the interface with Iapetus in the display frame:
Click the image to see the page and download the software. It's a 3-megabyte download. When you go to the download page, you'll see a "Download Unity Web" something-software button; yes, you need to click that, the instructions are just not very clear.
For more info about Cassini at Saturn and its moons, click here.
Best,
Chris