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