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