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