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