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