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