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