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