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