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