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