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