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