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