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