A library of pgf/tikz that requires lualatex can do graph drawing. It is called "graphdrawing" actually. It can do the layout automatically and so on. You can a

A library of pgf/tikz that requires lualatex can do graph drawing. It is called "graphdrawing" actually. It can do the layout automatically and so on. You can add new automatic layouts using lua. It's described in part IV of the pgf manual.