Over at Tiger Ears Penny made an extensive post explaining how you can see what region a wormhole leads to just by looking at its colors.
The guide shows two images for each destination region and a complete chart of wormhole class 1 through 6 both as source and destination.
A wormhole in my system looks like this:
I think that matches up pretty well with the second image of the Citadel region. Both show caldari grey with red and green clouds while no other region shares that same combination of colours.
Now everyone can predict the destination region or class before jumping through a wormhole. Awesome guide and I am definately going to reference it a lot.