It's not only possible, it's easy!
Click on the wire and then in the right hand Properties panel and then select the colour you want.
You can also select the line width and line style there too:
![Selecting line colour:][1]
[1]: /editor/20150718/55aa284ac74e8.png
Our website uses essential cookies to help us ensure that it is working as expected, and uses optional analytics cookies to offer you a better browsing experience. To find out more, read our Cookie Notice