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