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