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