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