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