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)(11,16)(12,24)(13,27)(14,26)(15,18)(17,30)(19,21)(20,36)(22,33)(23,32)(25,29)(28,34)(31,37)(35,38)(39,40)(1,3,5,4)(2,6,8,7)(9,11)(10,16)(12,19)(13,20)(14,23)(15,22)(17,31)(18,33)(21,24)(25,35)(26,32)(27,36)(28,39)(29,38)(30,37)(34,40)(1,3,5,4)(2,7,8,6)(9,12,24,10,15,26,14,18)(11,19,23,33,22,32,21,16)(13,25,30,17,29,27,28,34)(20,35,39,40,38,36,37,31)(1,4,5,3)(2,6,8,7)(9,13,15,29)(10,17,18,34)(11,20,22,38)(12,25,26,27)(14,28,24,30)(16,31,33,40)(19,35,32,36)(21,37,23,39)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.