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