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