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