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