One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,4,6)(3,5,7,8)(10,13)(14,16)(19,24)(20,22)(25,26,29,30)(27,33,35,31)(28,32,36,38)(34,40,37,39)(11,15)(14,16)(17,18,21,23)(19,20,24,22)(26,30)(28,36)(31,33)(34,37)(9,10,12,13)(11,14,15,16)(17,19,21,24)(18,22,23,20)(25,27)(26,31)(28,37)(29,35)(30,33)(32,40)(34,36)(38,39)(1,2)(3,5)(4,6)(7,8)(9,10)(11,14)(12,13)(15,16)(17,19)(18,20)(21,24)(22,23)(25,26)(27,31)(28,32)(29,30)(33,35)(34,39)(36,38)(37,40) involution — undirected(1,3,4,7)(2,5,6,8)(9,11,12,15)(10,14,13,16)(17,20)(18,19)(21,22)(23,24)(25,28)(26,32)(27,34)(29,36)(30,38)(31,39)(33,40)(35,37)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.