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