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