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