Graphvizでクラス図

digraph observer {
  graph [bgcolor="#00000000" ,fontsize = 10, ranksep = 1, nodesep = 1];
  node  [style="filled",fillcolor="#FFFFFF55" ,fontsize = 10
   ,fontcolor="#4E3F2F" ,shape = record,color=white];
 
  edge  [fontsize = 10,color=white];
 
  subject       [label = "{Subject|登録()\l解約()\lお知らせ()\l}"];
  observer           [label = "{Observer|更新()\l}"];
  subject->observer[arrowhead=onormal];
}