digraph {
    node [shape = circle, height = 0.6, fontname = "monospace", fixedsize = true, fontsize = 12];
    edge [fontname = "monospace", fontsize = 12];

    node [shape = circle];
    S; SX; START;

    node [style = filled];
    C; SO; SOO; SOOO; SXH; SXHH;

    START -> S [label = "\\"];
    START -> C [label = "[^\\\'\\\\\\n]"];
    S -> C [label = "[abfnrtv\\\'\\\"\\\\\\\?]"];
    S -> SX [label = "[Xx]"];
    S -> SO [label = "[0-7]"];
    SO -> SOO [label = "[0-7]"];
    SOO -> SOOO [label = "[0-7]"];
    SX -> SXH [label = "[0-9a-fA-F]"];
    SXH -> SXHH [label = "[0-9a-fA-F]"];
}