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