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