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