Dot syntax for Production company graph example

digraph G {

    subgraph productionfirm {
        style=filled;
        color=lightgrey;
        node [style=filled,color="#0080FF"];
        pf [label="Freecer manufacturer"]
        dev [label="Development"]
        prod [label="Production"]
        pm [label="Product Management"]
        sup [label="Support"]
        pf -> dev
        pf -> prod
        pf -> pm
        pf -> sup
        pm -> Peter
        dev -> Wendy
        dev -> Charlie
        sup -> Martin

    }



    start -> pf     


    start [label="Orgnization of Production Company",shape=Mdiamond];
}