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