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