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