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