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