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