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)(11,20,22,16)(12,14,18,24)(13,17,23,21)(25,26,32,31)(27,36,34,29)(28,33,40,39)(30,35,38,37)(1,2)(3,5)(4,6)(7,8)(9,11,15,22)(10,16,19,20)(12,13,18,23)(14,21,24,17)(25,27)(26,29)(28,35)(30,33)(31,36)(32,34)(37,40)(38,39)(9,11,15,22)(10,16,19,20)(12,13,18,23)(14,21,24,17)(25,28)(26,33)(27,37)(29,38)(30,36)(31,39)(32,40)(34,35)(1,3,4,7)(2,5,6,8)(9,12,15,18)(10,14,19,24)(11,13,22,23)(16,21,20,17)(25,29,32,36)(26,34,31,27)(28,38,40,30)(33,35,39,37)(9,13)(10,17)(11,18)(12,22)(14,16)(15,23)(19,21)(20,24)(25,30,32,38)(26,35,31,37)(27,33,34,39)(28,36,40,29)(9,14)(10,18)(11,21)(12,19)(13,20)(15,24)(16,23)(17,22)(25,31,32,26)(27,36,34,29)(28,39,40,33)(30,35,38,37)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.