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