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