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