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