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