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