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