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)(11,19)(12,17)(13,15)(14,18)(16,22)(20,23)(21,24)(25,26,29,30)(27,31,34,38)(28,35,37,32)(33,36,40,39)(1,3,4,7)(2,5,6,8)(10,15)(12,13)(16,23)(17,18)(19,24)(20,21)(25,27)(26,31)(28,36)(29,34)(30,38)(32,33)(35,40)(37,39)(2,6)(5,8)(9,11,14,22)(10,16,18,19)(12,20,13,21)(15,23,17,24)(25,28,29,37)(26,32,30,35)(27,33,34,40)(31,39,38,36)(9,12)(11,20)(13,14)(15,17)(21,22)(23,24)(25,26,29,30)(27,31,34,38)(28,35,37,32)(33,36,40,39)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.