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