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