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