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