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