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