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