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