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