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