Plotting of a population graph edge set using ggplot neumonic

a <- matrix( c(0,1,0,1,1,0,0,1,0,0,0,1,1,1,1,0),nrow=4)
rownames(a) <- colnames(a) <- LETTERS[1:4]
graph <- as.popgraph(a)
igraph::V(graph)$x <- runif(4)
igraph::V(graph)$y <- runif(4)
require(ggplot2)
ggplot() + geom_edgeset( aes(x=x,y=y), graph )

ggplot() + geom_edgeset( aes(x=x,y=y), graph, color="darkblue" )

require(grid)

## Loading required package: grid

ggplot() + geom_edgeset( aes(x=x,y=y), graph, directed=TRUE, arrow=arrow(length=unit(0.5,"cm")) )