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