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