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