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