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