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