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