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