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