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