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