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