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