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