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