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