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