[graph-tool] Long node labels are hidden by neighboring nodes

Dear all, I am trying to draw a graph the labels of which are rather long and overlap with neighboring nodes. Because of that some labels are hidden apparently according to the drawing order of the nodes. You can reproduce the effect by running the attached script in the same directory with the graph file. Is there any workaround for that issue. Do z-coordinates help at all? Cheers Yannis Panagis