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