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