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