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