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