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