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