This is quite easy. All you have to do is write an algorithm that dissects the graph into separate trees. Then you can write a small program that generates 4 vertices for each point per line and then connects them. These values must be stored in the VBO and IBO. After all lines are converted into sets of 4 points and connected and appended to the same VBO and IBO you can just spawn it and be done. You have to adapt it to this though: A new, community-hosted Unreal Engine Wiki - Announcements - Unreal Engine Forums
Since he has the nodes and not the lines it is easier, but if you want to analyze the image to extract the lines you have to perform image analysis and that is much harder.
HTH
