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