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