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