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)(25,26,30,33)(27,32,36,31)(28,37,38,29)(34,35,39,40)(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)(26,31)(28,34)(29,35)(30,36)(32,33)(37,40)(38,39) involution — undirected(1,3)(2,4)(5,6)(7,8)(10,15)(11,16)(13,22)(19,24)(28,38)(29,37)(34,39)(35,40) involution — undirected(3,6)(4,8)(9,11)(10,12)(13,18)(14,16)(15,20)(17,19)(21,24)(22,23)(25,28)(26,29)(27,34)(30,38)(31,35)(32,40)(33,37)(36,39) involution — undirected(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)(26,32)(28,39)(29,35)(30,36)(31,33)(34,38)(37,40)(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)(26,28)(27,35)(30,37)(31,34)(32,39)(33,38)(36,40)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.