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