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