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