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