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