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