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