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