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