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