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