n=2 Prime[5];
p=PrimitiveRoot[n];
{n,p}

Graph[Table[PowerMod[p,k,n]->PowerMod[p,k+1,n],{k,EulerPhi[n]}],DirectedEdges->True,VertexLabels->Placed["Name",Center],VertexSize->0.4,VertexStyle->LightOrange]