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