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