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