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