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