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