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