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