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