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