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