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