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