Option saying whether graph edges are drawn as arrows
DirectedEdges
CycleGraph[6, DirectedEdges -> True]
→ Graph[<6>, <6>]Graph[{1 -> 2, 2 -> 3, 3 -> 1}, DirectedEdges -> False]
→ Graph[<3>, <3>]GraphPlot[{1 -> 2, 2 -> 3, 3 -> 4, 4 -> 1, 2 -> 4, 4 -> 5, 4 -> 6}, DirectedEdges -> True]
→ -Graphics-