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