Welsh–Powell colouring

% coloring.tex -- Welsh-Powell colouring computed by Lua (option lua).
% The order, the size, the degree sequence and the number of colours
% are given by tkz-graph.  Engine : LuaLaTeX
\documentclass[border=3mm]{standalone}
\usepackage[lua]{tkz-graph}
\begin{document}
\begin{tikzpicture}
  \GraphInit[vstyle=Welsh]
  \Vertices[unit=2.5]{circle}{A,B,C,D,E,F,G}
  \Edges(G,E,F,G,B,D,E,C,D,A,C,B,A) \Edges(B,E)
  \tkzGraphColoring
  \node[align=left,anchor=north] at (0,-3.2)
    {Order \tkzGraphOrder, size \tkzGraphSize\\
     degree sequence \tkzGraphDegreeSequence\\
     \tkzGraphColorCount\ colours};
\end{tikzpicture}
\end{document}