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