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