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