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