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