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