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