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