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