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