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