Character Map Creator?

Hello, first time poster here.

I've seen these beautifully elaborate character map graphics around the Internet but for the life of me I can't figure out how they did it!

Is there any sort of mobile or desktop application that I can draw up character maps? Preferably if the end product is shareable in either image or link form...

If you don't know what I mean, it's like a diagram with characters, and lines connecting them all around to show who is linked to who.