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