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)(11,20)(12,17)(13,18)(14,16)(15,19)(21,24)(22,23)(25,26,32,29)(27,35,31,33)(28,37,30,34)(36,39,38,40)(1,3)(2,6)(4,8)(5,7)(9,11,15,14)(10,16,19,20)(12,21,13,22)(17,23,18,24)(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)(10,17,19,18)(11,21,14,22)(16,23,20,24)(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)(10,18,19,17)(11,22,14,21)(16,24,20,23)(25,29,32,26)(27,35,31,33)(28,34,30,37)(36,39,38,40)(1,4)(2,3)(5,6)(7,8)(9,14,15,11)(10,16,19,20)(12,22,13,21)(17,23,18,24)(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)(14,20)(15,19)(21,23)(22,24)(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.