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