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