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