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