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