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