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