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