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