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