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