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