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