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