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