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