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