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