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