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