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