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