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