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