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