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