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