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