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