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