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