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