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