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