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