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