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