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