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