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