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