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