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