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