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