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