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