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