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