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