Color vertices in state.draw()

In a NestedBlockModel, I'm trying to color the vertices from an underlying
property, and not from the grouping of the NestedBlockModel. I do the

import graph_tool as *
import graph_tool.all as gt
import numpy as np
g =["football"]
prop = g.new_vertex_property("int")
prop.a = np.random.randint(0, 10, len(prop.a))

state = gt.minimize_nested_blockmodel_dl(g)
state.draw(vertex_color=prop, output='test2.png')

The difference between the two drawings is that when I supply the
vertex_color, the boundary of the vertex will be colored differently.
However, in a large state that is almost hidden to the naked eye. How can I
color the whole vertex in a different color, not only the boundary?

Use vertex_fill_color.