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