digraph G {
    rankdir="RL";
    node [style=filled,color=grey,shape=circle]; A B C D E;

    B -> A
    C -> A
    D -> B
    D -> C
    E -> D

    A [style=filled,color=grey];
    B [style=filled,color=grey];
    C [style=filled,color=grey];
    D [style=filled,color=grey];
    E [style=filled,color=grey];

    A -> Am
    E -> Em

    subgraph cm {
        rankdir="BT";
        rank="same";
        C Cm
    }
    C -> Cm

    subgraph bm {
        rankdir="TB";
        rank="same";
        B Bm
    }
    B -> Bm

    subgraph em {
        rankdir="BT";
        rank="same";
        E Em
    }

    Am [shape=Mdiamond,style=filled,color=lightblue];
    Bm [shape=Mdiamond,style=filled,color=lightblue];
    Cm [shape=Mdiamond,style=filled,color=lightblue];
    Em [shape=Mdiamond,style=filled,color=lightblue];

}