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