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