Try the following:
digraph simpsons {
subgraph Generation0 {
rank = same
Abraham [shape = box, color = blue]
Mona [shape = box, color = pink]
AbrahamAndMona [shape = point]
Abraham -> AbrahamAndMona [dir = none]
AbrahamAndMona -> Mona [dir = none]
Clancy [shape = box, color = blue]
Jackeline [shape = box, color = pink]
ClancyAndJackeline [shape = point]
Clancy -> ClancyAndJackeline [dir = none]
ClancyAndJackeline -> Jackeline [dir = none]
}
subgraph Generation0Sons {
rank = same
AbrahamAndMonaSons [shape = point]
HerbSon [shape = point]
HomerSon [shape = point]
HerbSon -> AbrahamAndMonaSons [dir = none]
HomerSon -> AbrahamAndMonaSons [dir = none]
MargeSon [shape = point]
PattySon [shape = point]
SelmaSon [shape = point]
MargeSon -> PattySon [dir = none]
PattySon -> SelmaSon [dir = none]
}
AbrahamAndMona -> AbrahamAndMonaSons [dir = none]
ClancyAndJackeline -> PattySon [dir = none]
subgraph Generation1 {
rank = same
Herb [shape = box, color = blue]
Homer [shape = box, color = blue]
Marge [shape = box, color = pink]
Patty [shape = box, color = pink]
Selma [shape = box, color = pink]
HomerAndMarge [shape = point]
Homer -> HomerAndMarge [dir = none]
Marge -> HomerAndMarge [dir = none]
}
HerbSon -> Herb [dir = none]
HomerSon -> Homer [dir = none]
MargeSon -> Marge [dir = none]
PattySon -> Patty [dir = none]
SelmaSon -> Selma [dir = none]
subgraph Generation1Sons {
rank = same
BartSon [shape = point]
LisaSon [shape = point]
MaggieSon [shape = point]
BartSon -> LisaSon [dir = none]
LisaSon -> MaggieSon [dir = none]
}
HomerAndMarge -> LisaSon [dir = none]
subgraph Generation2 {
rank = same
Bart [shape = box, color = blue]
Lisa [shape = box, color = pink]
Maggie [shape = box, color = pink]
Ling [shape = box, color = blue]
}
Selma -> Ling [dir = none]
BartSon -> Bart [dir = none]
LisaSon -> Lisa [dir = none]
MaggieSon -> Maggie [dir = none]
}
Produces:
