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