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