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