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