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