digraph
  G { label="MDFA of ((ab|ba)*aa|(ab|ba)*bb)*(ab|ba)*";
 
rankdir=LR
start[shape =none]
start ->node_1
node_1 [label="M1", shape = doublecircle]
node_1 -> node_2 [label ="b"]
node_1 -> node_2 [label ="a"]
node_2 [label="M2", shape = circle]
node_2 -> node_1 [label ="a"]
node_2 -> node_1 [label ="b"]
}