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