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