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