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