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