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