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