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