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