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)(25,26,31,30)(27,32,36,39)(28,29,33,38)(34,35,40,37)(9,11,13,19)(10,14,15,17)(12,20,21,18)(16,24,23,22)(25,27)(26,32)(28,37)(29,34)(30,39)(31,36)(33,35)(38,40)(2,6)(7,8)(25,28,31,33)(26,29,30,38)(27,34,36,40)(32,35,39,37)(1,3,5,4)(2,7,6,8)(10,15)(14,17)(16,23)(22,24)(28,33)(29,38)(34,40)(35,37)(1,4,5,3)(2,8,6,7)(9,12,13,21)(10,16,15,23)(11,18,19,20)(14,22,17,24)(25,29,31,38)(26,33,30,28)(27,35,36,37)(32,40,39,34)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.