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