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)(11,17)(12,18)(13,16)(14,15)(19,21)(20,24)(22,23)(25,26)(27,35)(28,34)(29,32)(30,36)(31,33)(37,38)(39,40)(1,3,5,8)(2,6,4,7)(9,11)(10,12)(13,19)(14,18)(15,17)(16,20)(21,23)(22,24)(25,27,31,29)(26,32,33,35)(28,37,36,39)(30,38,34,40)(1,2,5,4)(3,6,8,7)(10,15)(11,18)(16,23)(19,24)(26,33)(28,36)(32,35)(37,39)(1,2,5,4)(3,6,8,7)(9,11)(10,12)(13,19)(14,18)(15,17)(16,20)(21,23)(22,24)(25,28,31,36)(26,34,33,30)(27,37,29,39)(32,40,35,38)(1,4,5,2)(3,7,8,6)(9,12)(10,11)(13,21)(14,17)(15,18)(16,24)(19,23)(20,22)(25,29,31,27)(26,35,33,32)(28,39,36,37)(30,40,34,38)(9,13)(10,16)(11,19)(12,20)(14,22)(15,23)(17,21)(18,24)(25,30,31,34)(26,36,33,28)(27,38,29,40)(32,39,35,37)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.