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