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