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