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