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