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