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