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