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