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