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