Label extends outside of node

Forcing text to extend outside of the node

digraph G {
  // Use fixedsize=true to fix the size of node.
  // Warning: The label will be cut if there is not enough space for the graph.
  //      Change width=3 to width=0.75, label will be cut.
  node [shape=circle, fixedsize=true];
  a [label="A", width=3];
  b [label="Long label extending outside of node", width=0.75];