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