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