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