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