graph g_colors {
  graph[fontname="'Source Sans Pro', sans-serif", fontsize=12.0, style=invis];
  node[shape=circle, fontname="'Source Sans Pro', sans-serif",
       fontsize=14.0, color="#d3d3d3", style=filled];

  white  [label="#ffffff", fillcolor="#ffffff"];
  red    [label="#ff9999", fillcolor="#ff9999"];
  green  [label="#ccff99", fillcolor="#ccff99"];
  blue   [label="#99e6ff", fillcolor="#99e6ff"];
  yellow [label="#ffffcc", fillcolor="#ffffcc"];
  orange [label="#ffcc99", fillcolor="#ffcc99"];
  gray   [label="#d3d3d3", fillcolor="#d3d3d3"];

  edge[style=invis]
  white -- gray --  yellow -- orange--  red -- green -- blue

  {rank=same; white,gray,yellow,orange,red,green,blue}
}