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