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