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