Wolfram Technology Guide: Fully Automated Graph Layout  previous | next 
3D Graph Layout
Mathematica automatically lays out graphs not only in 2D but also in 3D.
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GraphPlot3D[Table[i -> Mod[i^2, 75], {i, 75}], SelfLoopStyle -> None, 

 MultiedgeStyle -> None, 

 EdgeRenderingFunction -> ({Yellow, Cylinder[#, 0.1]} &), 

 VertexRenderingFunction -> ({Red, Sphere[#, 0.2]} &)]
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