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