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