fglを使えばよい。

import Data.Graph.Inductive
import Data.Graph.Inductive.Example
import Data.Graph.Inductive.Graphviz

m486 :: NodeMap String
m486 = fromGraph clr486

t1 :: Gr String ()
t1 = insMapEdge m486 ("shirt", "watch", ()) clr486

t2 :: Gr String ()
t2 = insMapEdge m486 ("watch", "pants", ()) t1

main = do putStrLn $ graphviz t2 "test" (0,0) (0,0) Portrait

これはDOT言語で出力される。

digraph test {
    margin = "0"
    page = "0.0,0.0"
    size = "0.0,0.0"
    rotate = "0"
    ratio = "fill"
    1 [label = "shorts"]
    2 [label = "socks"]
    3 [label = "watch"]
    4 [label = "pants"]
    5 [label = "shoes"]
    6 [label = "shirt"]
    7 [label = "belt"]
    8 [label = "tie"]
    9 [label = "jacket"]
    1 -> 4
    1 -> 5
    2 -> 5
    3 -> 4
    4 -> 7
    4 -> 5
    6 -> 3
    6 -> 8
    6 -> 7
    7 -> 9
    8 -> 9
}

pngで出力したいときにはdotに渡す。

$ ./gvtest | dot -Tpng > gvtest.png

参考

• Stern-Brocot 木 を Haskell + Graphviz で