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