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)(25,26,30,38,29,32,28,33)(27,34,35,31,37,40,36,39)(1,3)(2,5)(4,8)(6,7)(9,11)(10,16)(12,20)(13,21)(14,23)(15,22)(17,24)(18,19) involution — undirected(3,8)(5,7)(9,12,15,17)(10,13,18,14)(11,20,22,24)(16,21,19,23)(25,27)(26,31)(28,35)(29,37)(30,36)(32,39)(33,40)(34,38)(2,6)(5,7)(9,13,15,14)(10,17,18,12)(11,21,22,23)(16,24,19,20)(26,32)(31,39)(33,38)(34,40)(9,14,15,13)(10,17,18,12)(11,21,22,23)(16,20,19,24)(25,28,29,30)(26,33,32,38)(27,35,37,36)(31,40,39,34)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.