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