Create curved edges in a graph

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Hello,

It seems that I am only able to create rectilinear graphs in sage. e.g. $K_{13}$ in two concentric circles:

g = graphs.CompleteGraph(13)
_circle_embedding(g,[0,1,2,3,4,5,6],center=(0,0),radius=6,shift=0)
_circle_embedding(g,[7,8,9,10,11,12],center=(0,0),radius=12,shift=0)
g.show()

I'd like to add an image of what this code produces, but I don't have enough karma.

I want my edges to have curves; something like this Paley Graph.

Any ideas on how to do this?