One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,8)(4,6)(5,7)(9,10)(11,18)(12,16)(13,22)(14,17)(15,21)(19,24)(20,23)(25,26)(27,32)(28,38)(29,34)(30,36)(31,35)(33,40)(37,39) involution — undirected(3,4)(6,8)(9,11)(10,15)(12,19)(13,20)(14,21)(16,23)(17,18)(22,24)(25,27)(26,32)(28,34)(29,38)(30,37)(31,33)(35,40)(36,39) involution — undirected(1,3,5,4)(2,6,7,8)(9,12,14,13)(10,16,17,22)(11,19,21,20)(15,23,18,24)(25,28,30,40,31,39,29,32)(26,33,34,38,35,27,36,37)(9,13,14,12)(10,16,17,22)(11,20,21,19)(15,23,18,24)(25,29,31,30)(26,34,35,36)(27,37,33,38)(28,32,39,40)(1,4,5,3)(2,6,7,8)(11,21)(15,18)(19,20)(23,24)(27,33)(28,39)(32,40)(37,38)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.