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