One vertex per element, one color per generator, with an edge from x to x·s.
(9,10)(11,17)(12,15)(13,16)(14,19)(18,23)(20,22)(21,24)(25,26,32,38,31,35,30,36)(27,33,34,40,37,39,29,28)(2,6)(3,4)(9,11,13,19)(10,14,16,17)(12,20,21,18)(15,23,24,22)(25,27,31,37)(26,33,35,39)(28,38,40,36)(29,32,34,30)(1,2)(3,8)(4,7)(5,6)(25,28,31,40)(26,34,35,29)(27,36,37,38)(30,33,32,39)(1,3,5,4)(2,7,6,8)(9,12,13,21)(10,15,16,24)(11,18,19,20)(14,22,17,23)(25,29,31,34)(26,28,35,40)(27,30,37,32)(33,36,39,38)(1,4,5,3)(2,7,6,8)(10,16)(14,17)(15,24)(22,23)(26,35)(27,37)(29,34)(36,38)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.