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