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