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