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