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