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