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