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