Bijection f between graphs

digraph G {
  compound=true
  
  subgraph cluster0 {
  	label="G"
    a [label="a"]
    b [label="b"]
    c [label="c"]
    d [label="d"]
    e [label="e"]
  }
  
  subgraph cluster1 {
  	label="H"
    1 [label="f(a)"]
    2 [label="f(b)"]
    3 [label="f(c)"]
    4 [label="f(d)"]
    5 [label="f(e)"]
  }
  
  c->3 [ltail=cluster0,lhead=cluster1,label=f];
}