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