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