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