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