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