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)(11,14)(12,13)(15,16)(17,18,21,23)(19,24,22,20)(25,26)(27,31)(28,32)(29,30)(33,35)(34,39)(36,40)(37,38)(1,2)(3,5)(4,6)(7,8)(9,11)(10,14)(12,15)(13,16)(17,19,21,22)(18,20,23,24)(26,30)(31,33)(32,38)(39,40)(3,7)(5,8)(9,11,13,16)(10,15,12,14)(17,18,21,23)(19,20,22,24)(25,26)(27,33)(28,32)(29,30)(31,35)(34,40)(36,39)(37,38)(1,3)(2,5)(4,7)(6,8)(9,11)(10,15)(12,14)(13,16)(17,18)(19,20)(21,23)(22,24)(25,27)(26,31)(28,36)(29,35)(30,33)(32,40)(34,37)(38,39) involution — undirected(1,2)(3,8)(4,6)(5,7)(9,12,13,10)(11,14,16,15)(17,20)(18,22)(19,23)(21,24)(25,28,29,37)(26,32,30,38)(27,34,35,36)(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.