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