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