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