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