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