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