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