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