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