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