How to link vertical node with curve lines?

Mar 4, 2013 at 6:08 PM
Edited Mar 6, 2013 at 1:46 AM
I am using NodeXL to do some social network analysis,but there always some lines eclipse the nodes,and it will make some kind of confuse. I have seen some good maps drawn by others with curve lines that would not eclipse the nodes,like follows:
So, how to do this/