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