I imagine Jills to look something like http://fc07.deviantart.net/fs71/f/2010/207/b/5/Golden_Akatosh_by_Crazy_Cat009.jpg. A mass of divine flame and light, gathered in the form of a dragon. Though the forms of the Jills would, of course, be more subtle, more graceful, slimmer, sleeker, more feminine.
Either that, or they're ethereal, argentum moonlight, gathered into a similar shape.
What do you think Jills look like?