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