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