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