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