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