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