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