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