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