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