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