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