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