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