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