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