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