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