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