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