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