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