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