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