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