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