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