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