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