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