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