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