One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,7)(4,8)(5,6)(9,10,14,13)(11,12,16,15)(17,18)(19,24)(20,22)(21,23)(25,26,29,30)(27,33,35,31)(28,36,37,32)(34,38,40,39)(2,6)(4,7)(9,11,14,16)(10,15,13,12)(17,19)(18,20)(21,22)(23,24)(26,30)(28,37)(31,33)(34,40)(17,20)(18,22)(19,23)(21,24)(25,27,29,35)(26,31,30,33)(28,34,37,40)(32,38,36,39)(1,3)(2,7)(4,6)(5,8)(9,12)(10,11)(13,16)(14,15)(17,20)(18,19)(21,24)(22,23)(25,26)(27,31)(28,36)(29,30)(32,37)(33,35)(34,39)(38,40) involution — undirected(1,4,5,7)(2,8,6,3)(9,13,14,10)(11,15,16,12)(17,18)(19,24)(20,22)(21,23)(25,28,29,37)(26,32,30,36)(27,34,35,40)(31,38,33,39)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.