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