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