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