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