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