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