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