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