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