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