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