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