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