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