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