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