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