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