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