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