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