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