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