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