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