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