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