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