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