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