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