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