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