dot -Tpng -o example.png
to create png file. Or create ps file and then with ps2pdf a pdf file.

description of the graph

 digraph G {
  father -> son;
  father -> daughter;

or with label: father [shape=box,style=filled, color=red,label="dad"] -> son [style=bold, label="junior",color=blue]

For nodes which are partially devided we need type record.

 node [shape=record]

then we can use:

 employee [label="{emp|+money:int\l+name:string\l | + word(): void\l}" ]
\l is for left positioned text
{ | } for horizontal dashs

to describe both ends of an edge use head- and taillabel:

 edge [headlabel="1",taillabel="1..*"

For not directed edges we can use tool "neato" instead of dot and code:

 graph G {
   A -- B