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