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