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