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