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