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