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