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