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