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