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