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