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