(*  HOLT1.M
An example based on Holt's graph.
It is the Cayley graph of the group
   <a,b|a^31=b^5=1, ab=ba^2> 
(therefore elements of the form b^ia^j)
with generating set
 {ba, ba^5, ba^25, b^4a^3, b^4a^13, b^4a^15}
*)


ponot = Partition[
           Flatten[
             Table[
                {i,j}, {i,0,4}, {j,0,30}
                  ]
                 ], 2
                ] ;


Holt1=MakeGraph[ ponot,
  (
    (
      (#2[[1]]==Mod[#1[[1]]+1, 5])&&
      (#2[[2]]==Mod[1+(2*#1[[2]]), 31])
    )||
    (
      (#2[[1]]==Mod[#1[[1]]+1, 5])&&
      (#2[[2]]==Mod[5+(2*#1[[2]]), 31])
    )||
    (
      (#2[[1]]==Mod[#1[[1]]+1, 5])&&
      (#2[[2]]==Mod[25+(2*#1[[2]]), 31])
    )||
     (
      (#2[[1]]==Mod[#1[[1]]+4, 5])&&
      (#2[[2]]==Mod[3+(16*#1[[2]]), 31])
    )||
     (
      (#2[[1]]==Mod[#1[[1]]+4, 5])&&
      (#2[[2]]==Mod[13+(16*#1[[2]]), 31])
    )||
     (
      (#2[[1]]==Mod[#1[[1]]+4, 5])&&
      (#2[[2]]==Mod[15+(16*#1[[2]]), 31])
    )
  )&, Type->Undirected    ];

