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)(11,21,24,32)(12,25)(13,16)(14,19)(15,20)(17,23,33,29)(18,26)(22,31,37,40)(27,34)(28,30)(35,39,38,36)(1,3,4,8)(2,5,6,7)(10,16,20,19)(17,21,33,32)(18,30,34,25)(31,35,40,38)(3,8)(5,7)(9,11)(10,17)(12,22)(13,23)(14,29)(15,24)(16,21)(18,31)(19,32)(20,33)(25,38)(26,36)(27,39)(28,37)(30,35)(34,40) involution — undirected(2,6)(5,7)(9,12,13,26,15,28,14,27)(10,18,19,25,20,34,16,30)(11,22,23,36,24,37,29,39)(17,31,32,38,33,40,21,35)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.