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