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