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