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