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