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