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