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