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)(19,20,23,22)(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)(10,16)(12,19)(13,20)(14,22)(15,21)(17,23)(18,24)(25,27,29,35)(26,30,32,39)(28,33,36,34)(31,37,40,38)(9,12,14,10,15,17,13,18)(11,19,20,24,21,23,22,16)(27,33)(28,36)(30,37)(31,40)(34,35)(38,39)(2,6)(5,7)(9,13,15,14)(10,17,18,12)(11,20,21,22)(16,23,24,19)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.