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